https://github.com/libcgroup/libcgroup/pull/236

From d190c0c548b3219b75e4c399aa89186e77bbe270 Mon Sep 17 00:00:00 2001
From: Khem Raj <raj.khem@gmail.com>
Date: Tue, 23 Aug 2022 20:03:09 -0700
Subject: [PATCH] api: Use GNU strerror_r when available

GNU strerror_r is only available in glibc, musl impelents the XSI
version which is slightly different, therefore check if GNU version is
available before using it, otherwise use the XSI compliant version.

Signed-off-by: Khem Raj <raj.khem@gmail.com>
--- a/configure.ac
+++ b/configure.ac
@@ -183,6 +183,11 @@ AC_FUNC_REALLOC
 AC_FUNC_STAT
 AC_CHECK_FUNCS([getmntent hasmntopt memset mkdir rmdir strdup])
 
+orig_CFLAGS="$CFLAGS"
+CFLAGS="$CFLAGS -D_GNU_SOURCE"
+AC_FUNC_STRERROR_R
+CFLAGS="$orig_CFLAGS"
+
 AC_SEARCH_LIBS(
 	[fts_open],
 	[fts],
--- a/src/api.c
+++ b/src/api.c
@@ -4571,9 +4571,13 @@ const char *cgroup_strerror(int code)
 {
 	int idx = code % ECGROUPNOTCOMPILED;
 
-	if (code == ECGOTHER)
+	if (code == ECGOTHER) {
+#ifdef STRERROR_R_CHAR_P
 		return strerror_r(cgroup_get_last_errno(), errtext, MAXLEN);
-
+#else
+		return strerror_r(cgroup_get_last_errno(), errtext, sizeof (errtext)) ? "unknown error" : errtext;
+#endif
+	}
 	if (idx >= sizeof(cgroup_strerror_codes)/sizeof(cgroup_strerror_codes[0]))
 		return "Invalid error code";